Particle detecting apparatuses that have been used hitherto often aim to detect particles having a particle diameter of at least 100 nm. However, particles floating in a clean room in the manufacturing process of, for example, a semiconductor device have a particle diameter smaller than 100 nm.
To detect particles having such a small particle diameter, the particles may be condensed with a condensing component, such as moisture, to increase the particle diameter before the detection.
To condense the particles with the condensing component, it is necessary to introduce the particles into a condensing and growing unit and transport the particles therethrough while the interior of the condensing and growing unit is in a supersaturation state.
It is, however, difficult to detect whether the interior of the condensing and growing unit attains a desired supersaturation level. The particles are not sufficiently condensed with the condensing component immediately after the measurement is started and, as a result of this, a significantly small number of particles are detected. Thus, the detection accuracy of the particles is deteriorated.